In the provision of structures of various kinds, two converging structural elements frequently have to be coupled to each other.
Currently, locking elements are used which wrap around the converging heads of the elements, keeping them in the correct mutual position: in practice, by mutually clamping the structural elements, a very effective and stable connection is obtained, which however can be aesthetically poor.
Further, such locking elements are adapted for the mutual coupling of structural elements only at predefined and limited angles of incidence.
If it is necessary to couple structural elements which are incident at nonstandard angles, it is common practice to use connecting plates (in practice, plates which must be superimposed on both elements and are fixed by means of screws or the like to the surface of said elements) or threaded connecting means or the direct welding of the two mutually proximate facing ends.
These solutions are highly versatile and allow to adapt them perfectly to any type of joint.
However, the use of plates and/or threaded means leads to the provision of an aesthetically poor product, which has surfaces of discontinuity which can entail deposits of dirt (dust, et cetera) and possible rainwater infiltrations.
The solution that provides for welding leads to the provision of a product which is qualitatively and aesthetically ideal: however, the costs for welding in place (during the assembly of the structure) are extremely high and make this solution inapplicable for most low-cost small structures.
In particular, these solutions are of practical interest in outdoor structures, such as pergolas, covering canopy structures and the like, and structures constituted by generally metallic profiled elements which constitute beams and columns.